The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.

The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.

Date of Patent:
Feb. 24, 2015

Filed:

Jun. 18, 2010
Applicants:

Wilfried Weigel, Werne, DE;

Gerhard Wülfing, Velbert, DE;

Peter Rahms, Billerbeck, DE;

Inventors:

Wilfried Weigel, Werne, DE;

Gerhard Wülfing, Velbert, DE;

Peter Rahms, Billerbeck, DE;

Assignee:
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
E21D 23/26 (2006.01); E21D 23/18 (2006.01); F15B 19/00 (2006.01);
U.S. Cl.
CPC ...
E21D 23/26 (2013.01); E21D 23/18 (2013.01); F15B 19/005 (2013.01);
Abstract

A hydraulic circuit for longwall support for use in underground mining for supporting a longwall by means of a plurality of support shields incorporates a pressure monitoring device in the pressure line between the load maintaining valve and the shield control valve. The pressure monitoring device can be a device for monitoring the piston position of the shield control valve which device signals a deviation of the set position predetermined by the shield control device from the measured actual position of the piston of the shield control valve in the form of a deviation signal. It may also be a pressure sensor which signals the deviation of the set pressure predetermined by the shield control device from the measured actual pressure in the form of a deviation signal. Signaling can be acoustic or optical.


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